Heat exchanger and methods of forming fins in a heat exchanger

ABSTRACT

A method of forming fins in a heat exchanger having a metal body by skiving the metal body to form a first fin in a first orientation, and skiving the metal body again to form a second fin in a second orientation while straightening the first fin into a third orientation.

BACKGROUND OF THE INVENTION

Skiving may be generally used to produce a series of very fineintegrated shavings on a metal body and the shavings may all havegenerally the same shape and size. For example, a heat exchangermanufacturer may use the skiving technique to create metal fins wherethe fin of the heat exchanger then provides a way to transfer heat.Integral fins formed from the parent material have a significantlyhigher heat transfer coefficient versus fins which may be brazed orotherwise attached to the metal body.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, the present disclosure relates to a method of formingfins in a heat exchanger including providing a metal body includingfluid cooling passages, skiving the metal body to form a first finextending from a first surface of the metal body, with the first finhaving a body terminating in a tip and where the body is at a firstorientation with respect to the first surface, and skiving the metalbody to form a second fin extending from the first surface of the metalbody, with the second fin having a body terminating in a tip, and wherethe body of the second fin is at a second orientation with respect tothe first surface, and simultaneously shaping the first fin to orientthe body of the first fin in a third orientation with respect to thefirst surface.

In another aspect, the present disclosure relates to a heat exchangerincluding a metal body having an upper surface, a set of fluid passagesextending through at least a portion of a depth of the metal body wherethe set of fluid passages is formed along at least a portion of a widthof the metal body, and a set of fins skived from the upper surface, witheach of the set of fins having a body with a length and a laterallyextending tip, and where the body extends substantially along the widthof the metal body.

In yet another aspect, the present disclosure relates to an annularsurface cooler for an aircraft including a surface cooler metal bodyhaving a first surface configured to confront a peripheral wall of anannular fan casing and a second surface spaced from the first surface, aset of fluid passages extending through the metal body where the set offluid passages is formed along at least a portion of a width of themetal body, and a set of fins skived from the first surface, with eachof the set of fins having a body and a laterally extending tip and wherethe body extends substantially along the width of the surface coolermetal body.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 illustrates a partially cutaway view of a turbine engine assemblywith a surface cooler in accordance with various aspects describedherein.

FIG. 2 is a perspective view of an aft portion of a fan casing in theturbine engine assembly of FIG. 1.

FIG. 3 is an exploded perspective view of the fan casing of FIG. 2.

FIG. 4 is an exemplary cross-sectional view of the surface cooler of thefan casing of FIG. 3.

FIG. 5 is a perspective view of a metal body in the surface cooler ofFIG. 4 before and after the creation of a set of fins.

FIG. 6 is an axial cross-section view of the metal body of FIG. 5 duringformation of a first fin.

FIG. 7 is an axial cross-section view of the metal body of FIG. 6 afterformation of the first fin.

FIG. 8 is an axial cross-section view of the metal body of FIG. 5 duringformation of a second fin.

FIG. 9 is an axial cross-section view of the metal body of FIG. 8 afterformation of the second fin.

FIG. 10 is an axial cross-section view of the metal body of FIG. 5 withfins formed in accordance with one embodiment of the disclosure.

FIG. 11 is an axial cross-section view of the metal body of FIG. 5 withfins formed in accordance with a second embodiment of the disclosure.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Aspects disclosed herein relate to surface coolers in an engine such asan aircraft engine. The exemplary surface coolers can be used forproviding efficient cooling. Further, the term “surface coolers” as usedherein can be used interchangeably with the term “heat exchangers.” Asused herein, the surface coolers are applicable to various types ofapplications such as, but not limited to, turbojets, turbo fans, turbopropulsion engines, aircraft engines, gas turbines, steam turbines, windturbines, water turbines, and any environment where a heat exchanger maybe desired.

FIG. 1 illustrates an exemplary turbine engine assembly 10 having alongitudinal axis 12. A turbine engine 16, a fan assembly 18, and anacelle 20 can be included in the turbine engine assembly 10. Theturbine engine 16 can include an engine core 22 having at least onecompressor 24, a combustion section 26, at least one turbine 28, and anexhaust 30. An inner cowl 32 radially surrounds the engine core 22.

Portions of the nacelle 20 have been cut away for clarity. The nacelle20 surrounds the turbine engine 16 including the inner cowl 32. In thismanner, the nacelle 20 forms an outer cowl 34 radially surrounding theinner cowl 32. The outer cowl 34 is spaced from the inner cowl 32 toform an annular passage 36 between the inner cowl 32 and the outer cowl34. The annular passage 36 characterizes, forms, or otherwise defines anozzle and a generally forward-to-aft bypass airflow path. A fan casingassembly 37 having an annular forward casing 38 and an annular aftcasing 52 can form a portion of the outer cowl 34 formed by the nacelle20 or can be suspended from portions of the nacelle 20 via struts (notshown).

In operation, air flows through the fan assembly 18 and a first portion40 of the airflow is channeled through compressor(s) 24 wherein theairflow is further compressed and delivered to the combustion section26. Hot products of combustion (not shown) from the combustion section26 are utilized to drive turbine(s) 28 and thus produce engine thrust.The annular passage 36 is utilized to bypass a second portion 42 of theairflow discharged from fan assembly 18 around engine core 22.

The turbine engine assembly 10 can pose unique thermal managementchallenges and a heat exchanger or surface cooler, illustrated herein asan annular surface cooler 50, can be attached to the turbine engineassembly 10 to aid in the dissipation of heat.

FIG. 2 illustrates an aft casing 52 of the fan casing assembly 37 fromFIG. 1. The annular surface cooler 50 can be operably coupled to aperipheral wall 54 (FIG. 3) of the annular aft casing 52 and caninclude, but is not limited to, an air-cooled heat exchanger that ispositioned within the annular passage 36. While the surface cooler 50has been illustrated as being downstream of the fan assembly 18 it isalso contemplated that the surface cooler 50 can alternatively beupstream from fan assembly 18. As such, it will be understood that thesurface cooler 50 can be positioned anywhere along the axial length ofthe annular passage 36.

A partially exploded view of the aft casing 52 from FIG. 2 is shown inFIG. 3. The surface cooler 50 can include a circumferential and axialprofile that is substantially similar to the circumferential and axialprofile of the peripheral wall 54, and can cover any portion of thecircumference of the peripheral wall 54. The annular surface cooler 50can also include a metal body 60 having an upper surface 62 and a lowersurface 64, as well as a set of fins 80 spaced circumferentially alongthe metal body 60. It will be understood that a set of surface coolers50 can be utilized to cool a single turbine engine assembly 10, and alsothat “a set” as used herein can include any number including only one.

A circumferential cross-sectional view of the surface cooler 50, takenalong the line 4-4, is shown in FIG. 4. The metal body 60 of the surfacecooler 50 can further include an axial width 68, and the lower surface64 can be spaced apart a depth 66 from the upper surface 62 as shown. Afin 80 of the surface cooler 50 can have a body 84 that extends radiallyfrom the first surface 62 and terminates in a tip 86 which is unattachedfrom the bulk of the surface cooler 50. The body 84 of the fin 80 canhave a length 88 that extends substantially along the width 68 of themetal body 60 as shown.

The surface cooler 50 further includes a set of circumferential internalfluid cooling passages 70 having an inlet 71 and an outlet 73, and alsoextending through at least a portion of the depth 66 of the metal body60. The fluid cooling passages 70 also have a width 72 along at least aportion of the width 68 of the metal body 60, wherein the width 72 ofthe set of cooling passages 70 is defined as the combined width of allindividual cooling passages 70 and can be smaller than the length 88 ofthe fin 80 as shown. In addition, the surface cooler 50 can beconstructed such that a side 90 of a fin in the set of fins 80 can forma side angle 91 with a vertical reference line 92 as shown. It is alsocontemplated that either side of a fin in the set of fins 80 can formsuch an angle with respect to a vertical direction, and further, thatthe angles may be different between the two sides as desired. Inaddition, the surface cooler 50 can be constructed to create a differentside angle for different fins in the set of fins 80.

Arrows 56 (FIG. 2) illustrate exemplary fluid flow through the surfacecooler 50 and arrows 58 illustrate airflow that interacts with fins 80during operation. Heat can be transferred from the fluid within throughconduction to the remainder of the surface cooler 50 including the fins80. Heat can then be dispersed via convection to the airflow 58.

A method of forming the fins 80 is illustrated in FIGS. 5-9. In FIG. 5,the metal body 60 is shown before and after the creation of the set offins 80, and the metal body 60 is illustrated with a depth 66 and width68 as shown. The depth 66 and width 68 can be any suitable depth andwidth depending on the configuration of the surface cooler 50. While themetal body 60 has been illustrated as straight and rectangular it willbe understood that this is for clarity purposes only and that the metalbody 60 can be curved and contain any of the features used for mountingof the surface cooler 50.

In one non-limiting example, the metal body 60 and fluid coolingpassages 70 can be formed by an extrusion process. In such an instancean additional metal portion 75 can also be extruded onto the uppersurface 62 of the metal body 60. It is contemplated that the metal body60 and additional metal portion 75 can include an aluminum-based alloysuch as 1100 aluminum alloy; however, this example is not intended to belimiting, and any material suitable for the fan casing environment iscontemplated for the metal body 60 and additional portion 75. It isfurther contemplated that the metal body 60 and additional metal portion75 may be made from the same material, or the metal body 60 may be madefrom a different material from the additional metal portion 75, havingdifferent hardnesses or thermal properties suited for the intendedlocation of the surface cooler 50.

A skiving machine 300 having a skiving blade 302 and fin straightener306 can be used to create the fins 80 as shown in FIG. 6, which is anaxial cross-sectional view taken along the line 6-6 (FIG. 3). Theskiving blade 302 may be operably coupled to a cutter backing block orother machine which may apply a driving pressure to the skiving blade302. It is contemplated that a driving pressure may be applied in anysuitable manner that may exert a force on the skiving blade 302. Theskiving blade 302 may be advanced into the metal body 60 therebyproducing a first fin 81, which is formed at a leading edge 304 of theskiving blade 302.

The advancement of the skiving blade 302 may be stopped while the firstfin 81 is attached to the metal body 60 in a first orientation A asshown in FIG. 6. After forming the first fin 81, the skiving blade 302may be retreated from the metal body while the first fin 81 remainsattached in the first orientation A as shown in FIG. 7; in thisorientation, the body 84 of the first fin 81 forms an acute first angle100 with the first surface 62. The skiving blade 302 may then beadvanced again into the metal body 60 to produce a second fin 82 in asecond orientation B, similar to the first orientation A having an acutefirst angle 100 with the first surface 62 as shown in FIG. 8. Duringcreation of the second fin 82, the fin straightener 306 can contact anypoint along the body 84 of the first fin 81 and move it into a thirdorientation C in which the body 84 of the first fin 81 forms a secondangle 200 with the first surface, preferably 90 degrees as shown in FIG.9. Continuing in this manner, it can be appreciated that successiveadvances of the skiving blade 302 can simultaneously produce one fin inthe first or second orientations A, B while straightening apreviously-skived fin into the third orientation C, and the last fin inthe set of fins 80 may be straightened by the fin straightener 306without skiving any additional fins with the blade 302. It will beunderstood that while the first and second orientations are illustratedas being at the same at the same acute angle that this need not be thecase. Further, while the third orientation has been described as beingat 90 degrees it will be understood that the “straightened” orientationcan merely be straighter when compared to the first orientation.

In FIG. 10, a completed set of fins 80 is shown in accordance with afirst embodiment of the disclosure. The body 84 of a fin 80 creates a90-degree angle with the first surface 62 of the metal body 60,extending radially inward when assembled on the annular aft casing 52.

In FIG. 11, a completed set of fins 80 is shown in accordance with asecond embodiment of the disclosure. The second embodiment is similar tothe first embodiment; therefore, like parts will be identified with likenumerals increased by 100, with it being understood that the descriptionof the like parts of the first embodiment applies to the secondembodiment, unless otherwise noted. It is contemplated that a similarskiving machine having a skiving blade and a straightener may form a setof fins 180 out of an upper surface 162 of a metal body 160, where thefins 180 can have an arcuate cross-section as shown.

During operation, of the surface cooler 50 (FIG. 1) a hot fluid such asoil can be passed through the fluid cooling passages 70, proximal to theupper surface 62. Heat from the fluid may be conducted through the metalbody 60 and can be dissipated through the set of fins 80 to a coolingfluid passing by the fins 80. The cooling fluid can include, but is notlimited to, cooling air passing through the annular passage 36, which byway of a non-limiting example can be a bypass duct of the turbine engine10.

The above described embodiments provide for a variety of benefitsincluding that fins may be created at a faster rate than traditionalskiving methods; in one example, the present method could create 250fins per minute while moving them into the second orientation B.Additionally, the use of skiving methods can allow for less material tobe used during formation of the fins 80 compared to other manufacturingmethods such as machining, which can reduce the material costs of thesurface cooler 50. The present method also allows for the skiving offins from an extruded material containing pre-formed fluid coolingpassages 70, which can improve the thermal performance of the surfacecooler 50 due to fluid movement within the cooling passages 70.

In addition, the fins 80 created by skiving can be durable enough to beadjusted in position or shape using standard tools such as circular sawsor other abrasive means, including reshaping the fins 80 into arcuate orconical profiles based on the desired position of the surface cooler 50within the engine 10. The durability of the fins 80 can also improveresistance to impact damage from various sources such as foreign objectdebris.

It should also be appreciated that surface coolers having finsintegrally formed from parent material such as the metal body can have ahigher heat transfer coefficient compared to surface coolers having finscoupled to the parent material by various known attachment mechanisms,and the embodiments described above can provide for the more efficientmanufacture of surface coolers having integrally-formed fins with bettercooling ability. Further, the above described embodiments may be moreaffordable, repeatable, and more reliable which allows for predictablefin geometry at predictable spacing.

To the extent not already described, the different features andstructures of the various aspects can be used in combination with othersas desired. That one feature cannot be illustrated in all of the aspectsis not meant to be construed that it cannot be, but is done for brevityof description. Thus, the various features of the different aspects canbe mixed and matched as desired to form new aspects, whether or not thenew aspects are expressly described. Combinations or permutations offeatures described herein are covered by this disclosure.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A method of forming fins in a heat exchanger, themethod comprising: providing a metal body including fluid coolingpassages; skiving the metal body to form a first fin extending from afirst surface of the metal body, with the first fin having a bodyterminating in a tip and where the body is at a first orientation withrespect to the first surface; and skiving the metal body to form asecond fin extending from the first surface of the metal body, with thesecond fin having a body terminating in a tip and where the body of thesecond fin is at a second orientation with respect to the first surfaceand simultaneously shaping the first fin to orient the body of the firstfin in a third orientation with respect to the first surface.
 2. Themethod of claim 1 wherein the first fin comprises a fin that extendssubstantially along a width of the metal body.
 3. The method of claim 1wherein the body of the first fin in the third orientation includes anarcuate cross section.
 4. The method of claim 1 wherein skiving themetal body to form the second fin and simultaneously shaping the firstfin is accomplished via a single advancing motion of a skiving machinealong a lengthwise direction of the metal body.
 5. The method of claim 4wherein the skiving machine comprises a skiving blade and an operablycoupled fin mover.
 6. The method of claim 1 wherein skiving the metalbody to form the first fin comprises creating of a straight fin at anangle less than 90 degrees from the first surface.
 7. The method ofclaim 6 wherein shaping the first fin to orient the body in a thirdorientation comprises lifting the tip of the first fin away from thefirst surface.
 8. The method of claim 7 wherein shaping the first fin toorient the body in a third orientation comprises straightening the finto a more vertical position.
 9. The method of claim 8 wherein shapingthe first fin to orient the body in a third orientation comprises movingthe fin to a 90 degree angle with respect to the first surface.
 10. Themethod of claim 1 wherein providing a metal body including fluid coolingpassages comprises extruding the metal body.
 11. The method of claim 10wherein the metal body is formed from an aluminum-based alloy.
 12. Themethod of claim 1, further comprising shaping the second fin to orientthe body of the second fin in the third orientation with respect to thefirst surface.
 13. The method of claim 12 wherein the metal bodyincludes a predetermined angled surface that forms a leading edge of thefirst fin.
 14. A heat exchanger comprising: a metal body having an uppersurface; a set of fluid passages extending through at least a portion ofa depth of the metal body, where the set of fluid passages is formedalong at least a portion of a width of the metal body; and a set of finsskived from the upper surface, with each of the set of fins having abody with a length and a laterally extending tip and where the length ofthe body extends substantially along the width of the metal body. 15.The heat exchanger of claim 14 wherein the length of a fin of the set offins is greater than a width of the set of fluid passages.
 16. The heatexchanger of claim 14 wherein the body includes an arcuate crosssection.
 17. An annular surface cooler for an aircraft, comprising: asurface cooler metal body having a first surface and a second surfacespaced from the first surface and configured to confront a peripheralwall of an annular fan casing; a set of fluid passages extending throughthe metal body, where the set of fluid passages is formed along at leasta portion of a width of the metal body; and a set of fins skived fromthe first surface, with each of the set of fins having a body and alaterally extending tip and where the body extends substantially alongthe width of the surface cooler metal body.
 18. The annular surfacecooler of claim 17 wherein the body includes an arcuate cross section.19. The annular surface cooler of claim 17 wherein the width of the bodyis greater than a width of the set of fluid passages.
 20. The annularsurface cooler of claim 17 wherein the metal body comprises analuminum-based alloy body.